1. Field of the Invention
One or more embodiments of the present invention relate to a method of matching color and depth images, and more particularly, to an image matching method using a feature point of color and depth images.
2. Description of Related Art
Currently, information about a three-dimensional (3D) image is widely used in a variety of applications. In general, 3D information includes geometry information and color information. A color image may be obtained using a device such as a Charged Coupled Device (CCD) or Complementary Metal-Oxide-Semiconductor (CMOS) camera. A depth image may be indirectly detected from a plurality of color images using computer vision technology, or directly obtained using a depth camera.
Since the development of depth cameras in hardware is slow in comparison to a color image camera, a method of indirectly detecting a depth image using computer vision technology has been conducted in a conventional art. However, the method using computer vision technology is complex and inaccurate. Accordingly, a direct method using a depth camera is currently the focus of attention along with the development of depth camera in hardware.
According to a principle of depth camera, for example, light such as infrared (IR) light is irradiated to an object, and a Time of Flight (TOF) is measured by sensing reflected light to measure a distance (depth) from a depth camera to each part of the object.
Also, an intensity image may be obtained depending on an intensity of IR light sensed by a sensor. An intensity image is associated with information about a distance to an object and object status such as a color, temperature, brightness, and the like. Humans may identify an object through the intensity image more easily in comparison to the depth image.
When both color image and depth image of a single object is obtained, the color and depth images are generally measured from different viewpoints. Also, since a specification of a camera obtaining the color image is not the same as that of a camera obtaining the depth image, a resolution of the color image is usually different from that of the depth image. Accordingly, a method of matching color and depth images having different resolutions and viewpoints is required.